Got my new 400 L-disappointed that

I can't keep autofocus with a Kenko Pro 1.4 extender on it. I thought I had read that the Canon extenders wouldn't work but other brands would. Other than that it seems to be a sharp lens. Any comments?
Karen

It won't work. There is an older Tamron/Kenko model that will work, but not the latest versions with electrical connections.

Rats!

Somewhere in the teleconverter FAQ sticky thread at the top of the lens section, there is information on which teleconverters will "fool" the camera and allow autofocus. I believe that the "cheap" version of the Tamron 1.4X will work. There are a couple of others.

What will not work are the Canon, Sigma, and a couple of higher-priced "pro" versions from Kenko, Tamron, and perhaps others.

Well, guess I have to buy a cheap 1.2..how ironic. So will that ruin the quality of the pictures? (assuming I can take a decent picture...lol)
Karen

Is it a 400 f5.6? If so, AF will only be maintained with a 1D-series body...regardless of the brand.

rather than buy another one try to use tape first, i remember you can tape the last 3 pins but i dont know which one, there may be some people who have experience with it who can help you

Seriously? Put tape over the connectors? Wouldn't that hurt the connectors?
Karen

I've read about the tape too, but heard it was only one of the pins. But I don't think a 1.2 anything would even be worth the effort or the money for just a few extra feet of closeness.

canonloader wrote in post #2247711
I've read about the tape too, but heard it was only one of the pins. But I don't think a 1.2 anything would even be worth the effort or the money for just a few extra feet of closeness.

If I could get close enough I'd have been happy with my 200L 2.8! And about a grand richer! Hard to sneak up the vertical side of a silo....
Karen

pttenn wrote in post #2247688
Seriously? Put tape over the connectors? Wouldn't that hurt the connectors?
Karen

I have taped the last three pins on my Canon 1.4 tc for use with the 400mm f5.6. Cannot see how it would harm the connectors.
You will find that the af will hunt a bit but there are a few tricks to help it along.
1) Roughly manual focus first and then auto focus helps a lot to eliminate the hunting.
2) For birds in flight I depress the shutter and when it begins to hunt, release the shutter and then depress again.

There must be lots of people using converters with the pins taped and I have never heard of a problem.

Thats what I use the crop button for.

Karen, try this and see how you like it. It should work fine http://www.pbase.com …s/image/5331691​7/original

dputz wrote in post #2247638
Is it a 400 f5.6? If so, AF will only be maintained with a 1D-series body...regardless of the brand.

Not so - the cheap Kenko has not got the contacts to tell the camera that it is there so the Camera still thinks it is f5.6 and will af.

yes tape them or, better nail polish them